As habits and personal commitments build up it becomes increasingly difficult to fit in new ones. Despite our best efforts, some commitments that we know are good for us can fail to become automatic habits that require no willpower or attention to execute. Yet, since we recognize the importance, we remain committed, at the cost of some willpower and attention.
For example, I have the commitment to meditate every morning. And despite having done that for a long while now, it is still a small feat of willpower to do it, unlike, say, flossing or brushing my teeth. Every morning I devote a small amount of willpower to these commitments that aren't automatic habits, and that's fine. I've found my comfort zone and I am confident I can handle that long term.
But what happens when I'm interested in introducing a new habit? Suddenly that willpower pool is not sufficient. Building a new habit requires more resources than formed ones, as you need to remind yourself to do it, force yourself to do it, be mindful as you do it. Kind of like how a new physical activity can wear you out faster than an activity you're accustomed to, even if the latter is more intense.
Adding a new morning habit to an already ambitious morning is simply overstretching. Something's got to give.
This is where the principle of building one habit at a time kicks in, and the solution is to simply drop the established non-habits commitments, temporarily. This is ok, because picking them up once the new habit is established is a much faster process than starting them from scratch. Kind of like picking up an old habit, like playing the guitar or playing soccer.
If you find that your ability to introduce new habits is diminished, consider scaling back a bit from your current setup to introduce new space in your mind for properly adopting them. One habit at a time.